WordPress: redirect to loginpage for certain post caetgories if user is not logged in

Question

So I'm making a WP-site with some posts that should be only visible, I want to make this automatic (so user doesn't have to set to private each time for each post) and thought that a function would be neatest. So I want to redirect all visitors that is not logged in if they visit a post with the category Intranet .

I added this to functions.php, but nothing happened when visiting a post with this category:

add_action('intra_post', 'intranet_post_privacy');
function intranet_post_privacy() { 
    if ( !is_user_logged_in() && is_category( 'intranet' )) {
        header("Location: http://utt.se/user-login.php");
    }
}

Answer 1

Add below code to theme's functions.php change the $category_slug variable according to your category.

add_action( 'template_redirect', 'redirect_to_login_for_specific_category' );
function redirect_to_login_for_specific_category() {
    $category_slug = 'intranet';
    global $post;
    if ( ! is_user_logged_in() && in_category( $category_slug, $post ) ) {
        $new_url = site_url() . "/wp-login.php";
        wp_redirect( $new_url, 301 );
        exit;
    }
}